Improvement in pressure-gages



T. SHAW.

. PRESSURE GAGE. No.1,87,053. Patented If'eb. 6,4877.

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NPETERS, FHOTOL1THOGRA FHER, WASHINGTON, D. C

UNITED 11s PATENT Orrron THOMAS SHAW, OF PHILADELPHIA, PENNSYLVANIA.

IMPROVEMENT IN PRESSURE-GAGES.

Specification forming part of Letters Patent No. 187,053, dated February6, 1877; application filed October 18, 1876.

with mercury, and in the provision of stopcock and elastic cushion fortube, all for the purpose as hereinafter described.

The object of the invention is to enable the register of low pressuresin high-pressure gages, and to secure glass tube tightly without. riskof fracture, and to prevent possible loss of mercury while in transit,and to secure correct working when in operation, and is an improvementon my patent, No. 37,794, of February 24:, 1863, of which'i am soleowner.

In order to enable others to use and practice my invention, I willproceed to describe its construction and operation.

0n reference to the accompanying drawings, which form part of thespecification, the sketch represents avertical section through center ofgage, of which A is the metal base, provided with plungers O, the weightof which is caused to rest on spring N. The bottom and top of plunger 0is covered with sheet-rubber, (shown in heavy black line,) to preventleakage at joints of plunger. screwbutton that impinges on rubber atbottom, and E is an iron disk that impinges on rubber disk at top, beingforced down by screw-cap F. The concavity in center of iron disk E formsthe mercury-chamber D. B is a nut screwed into base A, and is providedwith tapped hole in center to enable attachment to any source ofpressure. Brass tube G is soldered to cap F and ring L. Said tube G isslotted in front side to enable the observance of rise of mercury inglass tube H. Figures Iis a' recording the pressure are marked on theoutside of brass tube. K is a stop cock, secured concentric in cap M,that screws into ring L. J is a rubber ring, forming acushion for theglass tube in recess in bottom of stopcock K, making it similar torubber cushion J in center of iron disk E, giving two elastic supportsto glass tube H, which lessens the liability to fracture.

The stop-cock K enables a convenient and ready means of shutting 0Emercury while the gage is in transit, and equal facility for opening themercury-tube to the atmosphere when in use.

The spring N is made of sufficient tension and strength to support theweight of the plunger 0, when loaded with mercury to any desired point.

This improvement enables the immediate registering of any appliedpressure beneath plunger 0. Without this improvement the pressure cannotbe shown until it has reached a point beyond the weight of plunger andits load of mercury.

It will be evident that the spring 0 can be variously fashioned andapplied to effect the same object.

What I claim, and desire to secure by Letters Patent, is

1. The combination, in a mercury steamgage, with the plunger 0, of aspring, N, supporting the plunger and its load of mercury, substantiallyas and for the purpose set forth.

2. The combination, in a mercury steamgage, with the tube, its cap M,and the mercury-reservoir, of a stop-cock, K, arranged as shown, toretain the mercury within the tube during transit, substantially as setforth.

3. The combination of the rubber cushion J and the gage-tube, beveled atits ends, so that the tube is cushioned in every directiomsubstantiallyas set forth.

THOMAS SHAW.

Witnesses:

W. HUGHES, WMQGARWOOD.

